The invention relates to a data processing apparatus with a programmable read-only memory, a central processor, and a keyboard for entering commands or data, in which the memory is arranged to contain data necessary for the operation of the apparatus.
Memories known by the name of PROM (programmable ROM) or EPROM (erasable programmable ROM) are read-only memories, and are programmed in order to durably preserve general data necessary for initializing the machine or for controlling its subsequent operation. PROM and EPROM memories are programmable one or more times respectively, by means of an electrical apparatus.
The advantage of using read-only memories of PROM and EPROM types lies in the facility for programming or updating the permanent data required by the apparatus. The need to update permanent data, which is important in any data processing system, is particularly felt in the case of electronic teleprinters, because such permanent data can determine the method of message communication, the automatic response, the line timing and other variable parameters, according to the local situation in which the machine is used. It is known to update such data by means of a suitable device separate from the apparatus in which the PROM or EPROM memory is used.
The object of the invention is to make updating of the data stored in PROM or EPROM memories more rapid and reliable, and to make the checking thereof more reliable.